Objectives This study investigated the effects of stress during pregnancy on responses of the offspring of stressed rhesus monkey mothers to later stress exposure in order to determine if neurobehavioral deficits observed in the infancy period were still present when the animals were studied as juveniles. ABSTRACT:Seven pregnant rhesus monkeys received stress in the form of movement from their home cages and exposure to unpredictable noise during midgestation (days 90 - 145 post-conception). Seven undisturbed pregnant mothers served as controls. At 2 yrs of age, offspring from both groups were compared in their behavioral, adrenocortical, and neurochemical responses to a baseline and four increasingly stressful procedures. Blood samples, CSF samples and behavioral data were collected under all conditions. Prenatally-stressed animals showed enhanced behavioral responses to stress as juveniles (Clarke & Schneider, 1993). Plasma ACTH values were significantly higher in the prenatally-stressed group under these conditions, but there was no difference in cortisol (Clarke et al, 1994). Offspring of stressed mothers also showed higher CSF concentrations of norepinephrine and DOPAC than control offspring under all conditions. At four years of age, the prenatally-stressed group showed an increased response to CRH challenge and a reduced response to dexamethasone challenge, as well as indications of aterations in circadian HPA axis activity. An important finding was that behavioral alterations were still evident in the prenatally stressed animals as adolescents the prenatally-stressed animals showed dramatic deficits in social and adaptive behavior at 4.5 years of age. These results suggest that offspring of mothers stressed during pregnancy may show enhanced vulnerability to stressors later in life, and concur with rodent findings indicating that early stress may have long-term effects on HPA axis and neurochemical regulation and behavioral responses to stress. Keywords prenatal growth, development, stress, HPA axis